Scalar-tensor models of normal and phantom dark energy
Keywords: reconstruction, Scalar tensor theory
Abstract
We consider the viability of dark energy (DE) models in the framework of the scalar-tensor theory of gravity, including the possibility of having a phantom DE at small redshifts z as admitted by supernova luminosity-distance data. For small z, the generic solution for these models is constructed in the form of a power series in z without any approximation. Necessary constraints for DE to be phantom today and to cross the phantom divide line p = -ρ at small z are presented. Considering the solar system constraints, we find for the post-Newtonian parameters that γPN < 1 and γPN,0 ≈ 1 for the model to be viable, and βPN,0 > 1 (but very close to 1) if the model has a significantly phantom DE today. However, prospects for establishing the phantom behaviour of DE are much better with cosmological data than with solar system experiments. Earlier obtained results for a Λ-dominated universe with the vanishing scalar field potential are extended to a more general DE equation of state confirming that the cosmological evolution of these models rules them out. Models of currently phantom DE which are viable for small z can be easily constructed with a constant potential; however, they generically become singular at some higher z. With a growing potential, viable models exist up to an arbitrary high redshift.
Más información
Título de la Revista: | JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS |
Volumen: | 2006 |
Número: | 9 |
Editorial: | IOP PUBLISHING LTD |
Fecha de publicación: | 2006 |
Página de inicio: | 016 |
Página final: | 016 |
URL: | http://stacks.iop.org/1475-7516/2006/i=09/a=016?key=crossref.c386a6d4e88ef5efa14a8b5dd3c83497 |
DOI: |
10.1088/1475-7516/2006/09/016 |